var f1, f2 : text;
    T, N, i, c, ip, j : longint;
    a : array[1..100] of byte;
begin
  assign(f1,'cifra.in');
  assign(f2,'cifra.out');
  reset(f1);
  rewrite(f2);
  readln(f1,T);
  while not eof(f1) do
    begin
      readln(f1,N);
       c := 0;
      for i := 1 to N do
        begin
          ip := 1;
          for j := 1 to i do
            ip := ip * i;
          a[i] := ip mod 10;
          c := c + a[i];
        end;
       writeln(f2,c mod 10);
    end;
  if T = 0 then write(f2,T);
  close(f1);
  close(f2);
end.